Air-compressor.



Patented my 3o, mon

D, PRYDE &. H. GAUEBMAN.

AIR COMPRESSOR.

(Application Jd Aug. 24, 1 900.)

2 Sheets-Sheet 2.

lNo Model.)

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ma uonms wnsns ca. PHUTuLIYHa. wxsnmnon, n. c,

. but by reason of its being movable it is diffi- NiTn STATES DAVID PRYDE AND HENRY GAUERMAN,

ASSIGN ORS TO THE BRADDOCK MACHINE MANUFACTURING COMPANY OF SAME PLACE.

OF BRADDOCK, PENNSYLVANIA lR-COIVPRESSOR.`

SPECIFICATION forming para of Letters Patent No. 679,335, dated July 3o, 1901.

Application iiled August 24, 1900.

To all whom, it may concern:

Be it known that we, DAVID PRYDE and HENRY GAUERMAN, residents of Braddock, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Air-Compressors; and we do hereby declare the following to be a full, clear, and exact description thereof.

Our invention relates to apparatus for compressing air, and is an improvement upon the patent granted to Edwin E. Slick, No. 620,983. In the patent to Slick the cylinder of the aircompressor has stationary heads provided with valves and a movable body provided with an annular row of air-inlet ports at the end thereof, the ends of said body fitting over the stationary heads and movable thereon to alternately open and close said inlet-ports. The cylinder-body is very heavy, so that it requires considerable power to move the same, and the weight causes it to wear rapidly. Furthermore,tl1e compression of the air heats the cylinder rapidly, and it should be cooled;

cult to make the proper Water connections thereto. It is the object of our invention to overcome these difficulties and objections to the Slick air-compressor; and to this end it consists in making the cylinder-body stationary, so that the same can be easily waterj acketed,and providingsupplementarymeans for opening and closing the air-inlet ports in the same.

To enable others to 4construct and use our invention, we will now describe the same more fully, referring to the accompanying drawings, in which- Figure 1 is a plan View of the compressor and driving means. Fig. 2 is a side elevation of the compressor and power-cylinder. Fig. 3 is an end view of the apparatus, and Fig. 4 is a vertical longitudinal section through the air-compressor.

Our air-compressor comprises a cylinder the body 1 of which is mounted immovably upon the bed-frame 2 and is provided with a water-jacket 3 and with an annular row of air-inlet ports 4 4 at each end. Also immovably mounted upon the bei-frame 2 are the stationary heads 5 and 6, the latter being perforated to allow the rod 7 of the piston 8 to Serial No. 27,875. (No model.)

pass therethrough, a suitable stuffing-box 9 being formed on the outside of said head. The heads 5 and 6 project into the cylinderbody 1, but are smaller than the interior of the latter, thereby leaving annular spaces in which are located the movable rings 10 10, which closely fit the exterior of the heads 5 and 6 and the interior of the cylinder-body 1. Suitable packing 1l 11 is provided to render the joints air-tight. The piston is reduced on each side, as at 8a, an amount equal to the thickness of the rings 10, thereby forming a' projecting portion 9 on each face of the piston. The rings 10 are provided with annular flanges 12, which have diametrcally opposite perforated ears 13 13, to which are secured the connecting-rods 14 14. These rods are mounted to reciprocate in perforated lugs 14 on the sides of the cylinder-body 1. Adjustably secured to the rods 14, as by means of set-screws, are collars 15, which are connected by means of links 16 to the upper end of arms 17 secured to the rock-shaft 18, mounted on the bed-plate 2. When the shaft 18 is rocked, it will, through the arms 17, links 18, and sliding rods 14, move the rings 10 10 to alternately cover and uncover the ports 4 in the cylinder-body, as will be readily understood.

The heads 5 and 6 are hollow to allow water to circulate therethrough and are provided with three chambers 19 for the piston-valves 20. Each of these valves is placed in a casing 21, which extends from the outer side of the head through the chamber 19 to the inner side of the head, said casing being removably held in place by means of the caps 22. Each casing 21 is contracted at its inner end, as at `23, to form a seat for the valve 20, and just back of said valve the casing is perforated, as at 24, to allow the compressed air to escape into the chamber 19, which communicates with an annular chamber 25. The chambers 25 at the two ends of the cylinder .are connected by means of the service-pipe27`. Each of the casings 21 is divided by the diaphragm 28 into two chambers, the outer one thereof, 29, serving as a cylinder for the piston 30, which is connected to the stem of the valve 20. A spring 31 bears at one end against the piston 30 and at its opposite end against the IOO IOl

- slide 39.

removable cap 22, said spring tending to hold the valve seated. The opening through the diaphragm is slightly larger than the vvalvestem, so that when the valve 2O is forced Vfrom its seat against the tension of the spring 3l compressed air will leak into the chamber 29, so that when the main piston S moves in the opposite direction the air in saidV chamber acts as a cushion and prevents the springs 3l from violently seating the valves 20. The construction of the valves and of the heads at the two ends of the cylinder are identical.

The rod 7 of the main piston 8 is connected at its opposite end to a piston in the cylinder 32, said cylinder being connectedat one end to the frame 33 and connected at its opposite end to the compressor-cylinder by means of rods 34. This cylinder is an ordinary steamcylinder provided with steam inlet and outlet connections 35 and 36 to the steam-chest 37, in which moves the usual valve, the connecting-rod 38 of vwhich is connected to the Also connected to the piston in the cylinder 32 is a rod 40, which is connected by apitman 4l to a crank on the shaft 42, said shaft being suitably mounted, as shown, and provided with the heavy ily-wheel 43, which gives the required momentum and steadiness to the apparatus. On the shaft 42 are two eccentrics, one of which is connected by a suitable strap andl rod 43 to the slide 39 for Y moving the valve in the steam-chest 37, the

other eccentric being connected bya similar strap and rod 44 to the outer end of an arm 45 on the end of the rock-shaft 18 for moving the rings 10 to alternately open and close the ports 4. v l

The operation of the apparatus is as follows: The movement of the piston in the power-cylinder 32 rotates the shaft 42 and also reciprocates the piston 8 in the compresser-cylinder l. The eccentrics on the shaft 42 are so located with reference to cach other that as the main piston 8 moves toward the head 5 of the compressor-cylinder the ring l0 on that end of the cylinder will be in its innermost position, as shown in Fig. 4 of the drawings, thereby closing the ports at that end of the cylinder, so that as the piston 8 travels toward the head 5 air is drawn through the ports 4 at the opposite end of the cylinder, while the air between said piston and the head 5 is compressed, thereby unseating the valves 20 at that end of the cylinder and forcing the air through the perforations 24 into the chamber 25, from which it passes to the driving all of the air in the cylinder past the outlet-valves 20. It follows that all of the air in the cylinder is forced past the outletvalves, none being compressed in wastespaces, so that the efficiency of the compressor is very high. As soon as the piston S starts to move in the opposite direction the rings 10 l0 are shifted, so that the ports at the end of the cylinder adjacent the head 5 are opened,

while those at the opposite end of the cylinder are closed, whereby the piston 8 compresses the air in the cylinder l and forces the same through the valves in the head 6, as before' described in connection with the head 5, and at the same time draws air in through the ports 4 adjacent the head 5. As soon as the piston 8 again begins to move toward the head 5 the rings l0 are again shifted to the position shown in Fig. 4, thereby forcing compressed air through the valves in the head 5 and drawing air into the opposite end of the cylinder, and so on. When the compressed air is forced past the valves 20, a portion thereof leaks around the valve-stems into the chambers 29 and underneath the pistons 30, and as soon as the main piston 8 reverses its movement the springs 3l will seat the valve 20; but this seating will be practically noiseless, since the compressed air beneath the pistons 30 is conned between the same and the diaphragms 28and-canescape but slowly, so that it serves as a cushion and prevents the violent seating of the valves 20.

By making the cylinder-body 1 stationary `and providing supplementary means for openv increased.

Instead vof using the cylinder for compressing air the same can be readily adapted for use as a vacuum-pump, in which case it would be merely necessary to cover the air-inlet ports 4 4 by hoods, which would form annular chambers around the ends of the cylinderbody over the air-iulet ports 4 4. These an nular chambers would be joined to a common inlet-pipe, which would be provided with means for attaching the same to the chamber or pipe in which the vacuum is to be produced. In other particulars the construction would be the same as shown in the drawings and the mode of operation would not be modified, the only difference being that instead of drawing the air through the ports 4 directly from the atmosphere it would be drawn from the chamber or pipe in which the vacuum is IOO IIO

to be produced. Such modification of the invention We intend to include in the terms o the claims.

What We claim, and desire to secure by Letters Patent, is

l. In an air-compressor the combination with a cylinder having a stationary body and heads, said body being provided with an annular roW of air-inlet ports at each end, of a piston in said cylinder, rings movable over said heads and projecting into said body, and means for moving said rings to alternately cover and uncover said ports.

2. In an air-compressor the combination with a cylinder having stationary heads provided With outlet-valves and a stationary body provided with airinlet ports at its ends, of a reciprocating piston in said cylinder, rings movable over said heads and projecting into said body, and means for reciprocat- "ing said rings to alternately cover and nn- F. W. WINTER, ROBERT C. TOTTEN. 

